Lots of people like to define sin, so done, via different definitions, such as, for instance, in the disobeying of societies’ laws, or the disobeying of what humankind has defined as God’s law, or the disobedience to Natural law, and even of not doing what should be done in a particular situation; of which, all these are readily defined as sin, along with many other things of this sort. Most people have a pretty good understanding of what sin is and pretty much know when they have sinned or not, though there are always going to be those people that are just plain ignorant or pretend to be such, even when they have done something wrong that is pretty unequivocal, when viewed fairly by outside parties.
Yet, there is another way to define sin, which while having similarities to the orthodox way of looking at sin, is different and profound in its own way. In point of fact, sin, is best defined as anything that breaks us from or has the effect of breaking our connection to, and thereby losing our friendship with God. So basically, anything that separates us from God and therefore the good attributes of God, which thereby places us outside of our proper harmony with God, is that which is sin, big or small.
God should be our best friend, for God always gets it right, and God will never let us down; so then, to the degree so possible in our relationships with others, we find that those relationships are true, to the extent that each party represents in action -- love, forgiveness, justice, and faithfulness. Anything less than that, doesn’t mean that our relationships have no value, but rather represents that there are improvements that need to be made to our character so that we can be of better temperate and by the virtue of being better, this means that we are therefore sinning less and less.
The first fundamental step in reducing our sinfulness, is to keep front and center in our mind’s eye, that in each and every interaction that we have with anybody, that we always will the good of that other person or entity. That is to say, to not will the good of the other, is, by definition, sin; because when we do not wish for the best for somebody else, or actively make sure that the other person will be “cheated” through our actions or our inaction in some respect, then we have willfully made a decision that is meant to harm, hurt, or to damage another, which is wrong.
So too, any and everything that takes us away from God, because we know that act is wrong, which thereby infringes upon our good relationship with God, is sin. It should be noted that it isn’t that our relationships with others in this world is somehow always going to be in enmity with our relationship with God, but rather, those personal relationships should serve to strengthen our friendship with God, so demonstrated by our good and righteous behavior one with another. We are, always, in every minute of every day, representatives of God, so meant to prove to ourselves as well as to others, as to whether or not we are good stewards of the responsibilities so vested in us, or whether we are irresponsible, confused, and purposefully ignorant of who and what we really are, as children of God.